Filter elements having pleated filter media are well known in the art. Pleated filter elements are often used to remove particulate contaminants from a gaseous fluid stream, such as in an intake air stream. Varieties of pleated filter elements find applications in automotive engine intake systems, air compressor systems as well as in other process and equipment applications where the removal of contaminants is highly desired or required.
Depending upon the filter type and application, pleated filter media may be susceptible to collapsing or folding over of pleats onto adjacent pleats due to fluid forces applied to the pleats by the filtered fluid stream. This can occur as the pleated filter media is generally made from a thin filter paper or other porous sheet media that is advantageously flexible enough to be formed into pleats. The thickness and material chosen for use as a filter media needs to have filter pores of sufficient size to pass the fluid stream while blocking passage of undesired contaminants. Generally the use of thinner rather than thicker filter media elements is preferred so as to reduce the pressure drop across the filter.
Several solutions have been developed over time to address improved support for filter pleats. In some cases a porous plastic or metallic sheet is provided as a supportive backing sheet to the filter element. This approach, while providing some support to the filter media sheets, does little to support the filter media pleats, permitting the pleats to be folded over or collapsed by the fluid forces applied to the filtration media by passage of the filtered fluid.
Another improvement is provided in U.S. Pat. No. 6,524,479 which discloses a pleated filter element including a fold support member in the shape of a rod that pierces the pleat surfaces of the folds of the filter media, thereby supportively joining adjacent pleats and regulating spacing of the pleats. This solution requires that holes for the rod be provided through the filter media, and the presence of any holes may be susceptible to leakage of unfiltered fluid around the filter media.
As can be seen, there is a need for a pleated filter element that includes a support structure configured to resist fluid forces so as to retain filter media pleats in a spaced and fully erect arrangement and that overcomes limitations of the prior art.